1. Field of the Invention
This invention relates to underwater acoustic sources and especially to an underwater acoustic source using a moving piston, pulse engine as an acoustic generator.
2. Description of the Prior Art
Acoustic systems have long been used for communication with submarines and for sonar detection of submarines. It is difficult, if not impossible, to establish radio-wave communication with submerged vessels since penetration of sea water by electromagnetic waves is poor. Thus, acoustic systems offer the best means of communication with a submerged vessel. However, submarines today have world-wide ranges and communication may have to be effected over vast distances. Similarly, shore installations may desire to monitor the positions of submarines thousands of miles distant from the location of the shore installation. Acoustic generators producing high values of acoustic power (i.e., pressure) are required for such classification and monitoring applications. In addition it might sometimes be desired in military applications to use acoustic signals to “jam” communications between enemy vessels or to interfere with their sonar detection attempts.
Electromagnetic and piezoelectric transducers, for example, are presently available for this work, but must be used in directive arrays to obtain sufficient power for long-distance applications. This poses serious installation and durability problems since the transducers must be installed in the ocean, in a specific orientation and with precise timing and repeatability of the acoustic pulses.